I have my 3Gs and am jailbroken on 3.1.3 and have been for a long time. I cannot think of anything specific that I have done recently, but something has CERTAINLY changed. I was at 80% about 4-5 hours and left it on my table - didn't use it at all. I just went to check it and it was DEAD - requiring me to plug in to charge. Recently it has been running down very quickly for no apparent reason... I have checked the running processes through sbsettings and nothing else running. I don't use backgrounder, etc. Any ideas what I should/can do?